Elastic hydrophilic non woven fabric and fabrication method thereof

ABSTRACT

An elastic hydrophilic non-woven fabric is provided, which is made from composition grains using a meltblown process. The composition grains include 3 to 30 parts by weight of a hydrophilic auxiliary agent and 70 to 97 parts by weight of a hydrogenated styrene based triblock copolymer based on 100 parts by total weight. The hydrophilic auxiliary agent includes polylactic acid and polyvinyl acetate. A method that the elastic hydrophilic non-woven fabric is fabricated at least includes a step to melt the composition grains to form a melt body, and a step to squeezed the melt body through a spinneret by the meltblown process, then the elastic hydrophilic non-woven fabric is finished. Hence, the elastic hydrophilic non-woven fabric has both of elasticity and hydrophilicity.

FIELD OF THE INVENTION

The present invention relates to household supplies, and more particularly to an elastic hydrophilic non-woven fabric.

BACKGROUND OF THE INVENTION

Development of lighter and thinner elastic non-woven fabric is accompanied with progressing in textile industry, so that masks, diapers, wipes, medical sanitary materials, and sportswear of usages are applicable. A method for imparting elasticity to the non-woven fabric has been proposed in Patent Literature 1, which disclosed that a thermoplastic elastomer is used as material to fabricate the non-woven fabric by filament spinning and bonding method (hereinafter referred to as spunbonded). There are also Patent Literature 2 and 3 disclosed a method using a low crystalline polypropylene. The proposed method proposed that a high crystalline polypropylene or a mold release agent is added to the low crystalline polypropylene. Otherwise, there is also Patent Literature 4 disclosed a laminated multilayer structure comprising a low crystalline polypropylene non-woven fabric and a stretchable spunbonded non-woven fabric.

However, it is impossible to obtain the elastic non-woven fabric with excellent elasticity due to satisfying long fiber to be aligned structure easily in facial direction during fabrication of the spunbonded non-woven fabric. In terms of materials, the use of the low crystalline polypropylene must increase added amounts of the high crystalline polypropylene or the mold release agent. As a result, the obtained spunbonded non-woven fabric tends to have a greater residual strain and to exhibit poor stretchability. Besides, it is difficult to bring living applicable hydrophilicity to the non-woven fabric, by reason that polypropylene, the mold release agent, or other auxiliary agents usually has more hydrophobic functional groups.

In terms of process, a hot-melt process is mostly applicable, by which the non-woven fabric made from thermoplastic polymer is heated and pressured (such as hot-pressing or hot air bonding) to melt thermoplastic polymer and bond each other, so as to carry out bonding force. However, hand feeling is changed after the hot-melt process. The larger the melted area is, the harder the hand feeling is. Besides, the hot-melt process has disadvantage of poor elasticity. The reason is that a melted part of the non-woven fabric is similar to a plastic sheet, and an non-melted part is still fiber, the tensile property of the plastic sheet is greatly different from the fiber. The elasticity would be affected if the hot-pressing method is utilized for bonding.

CITATION LIST Patent Literature

-   Patent Literature 1: JP-A-H07-503502 -   Patent Literature 2: JP-A-2009-62667 -   Patent Literature 3: JP-A-2009-79341 -   Patent Literature 4: WO2012/070518A1

SUMMARY OF THE INVENTION

In order to solve aforesaid problems, it is an objective of the invention is to provide an elastic hydrophilic non-woven fabric which has micron class of fiber diameter, good elasticity of its fiber, and a draw ratio suitable for mask appliance. In addition, a surface of the non-woven fabric has a hydrophilic effect so as to absorb beauty essence and care lotion on the surface of the non-woven fabric.

It is another objective of the invention is to provide a method to fabricate the elastic hydrophilic non-woven fabric by using a meltblown process which is single process and uncomplicated. The non-woven fabric can be adjustable to have balance between hydrophilicity and elasticity by using raw materials providing biodegradability, hydrophilicity and elasticity, and by searching constituent ratio to achieve the best performance.

According to above objectives, the present invention provides an elastic hydrophilic non-woven fabric formed by a fiber made from composition grains using a meltblown process, the composition grains include 3 to 30 parts by weight of a hydrophilic auxiliary agent and 70 to 97 parts by weight of a polyolefin based elastic copolymer, the hydrophilic auxiliary agent includes a polylactic acid and a polyvinyl acetate.

According to above objectives, the present invention provides a fabrication method for an elastic hydrophilic non-woven fabric, comprising following steps: forming grains, the grains are formed by mixing 3 to 30 parts by weight of a hydrophilic auxiliary agent and 70 to 97 parts by weight of a hydrogenated styrene based triblock copolymer, wherein the hydrophilic auxiliary agent includes polylactic acid and polyvinyl acetate; melting the grains to form a melt body; and performing a meltblown process on the melt body, the melt body is squeezed by a spinneret, and then formed a fiber for fabricating the elastic hydrophilic non-woven fabric.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view depicting a flow chart of the fabrication method for the elastic hydrophilic non-woven fabric in accordance with the present invention.

FIG. 2 is a schematic view depicting the meltblown process on the composition grains in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The accompanying contents, which are incorporated in and constitute a part of this specification, illustrate the disclosed various embodiments, and together with the description, serve to explain the principles of the disclosed embodiments. As used herein, the terms “include,” “comprises,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or product.

In order to fabricate elastic masks having hydrophilicity on its surface, the present invention uses polyolefin based elastic copolymer and hydrophilic auxiliary agent as raw materials to be mixed at room temperature to form composition grains. Then perform the meltblown process on the composition grains to form fiber filaments. Next collect the fiber filaments to be fiber web which can be cut into strips of the non-woven fabric. On basis of the non-woven fabric suitable for masks, polyolefin based elastic copolymer may apply for example hydrogenated styrene based triblock copolymer represented as ABA. Wherein A is a monoalkenyl arene block chain, B is a conjugated alkadiene block chain. Typical ABA type block copolymer can be such as SBS, SIS, and S-EB-S. In preferred embodiment, applied hydrogenated styrene based triblock copolymer is selected-hydrogenated monoalkenyl arene-conjugated alkadiene-monoalkenyl arene. Wherein monoalkenyl arene is perfectly styrene, conjugated alkadiene is perfectly butadiene such as 1,3-butadiene, 1,4-butadiene or 1,2-butadiene. Usually, hydrogenation of conjugated alkadiene is performed via any known process in the prior art such as partial hydrogenation or selective hydrogenation.

In preferred embodiment, in the case of styrene-butadiene-styrene block copolymer such as SBS, selective hydrogenation of conjugated alkadiene block chain transforms SBS into S-EB-S. Butadiene block chain containing 1,4-addition and 1,2-addition of monomers is hydrogenated to form an ethylene/butene structure named as EB. EB is hydrogenated polybutadiene block chain. S is polystyrene block chain. In other words, the preferred polyolefin based elastic copolymer is hydrogenated styrene based triblock copolymer (abbreviated as S-EB-S) composed of styrene, ethylene, and butadiene. In detail speaking, polyolefin based elastic copolymer is a linear triblock copolymer composed of polystyrene as terminal end and ethylene-butene copolymer obtained by hydrogenation of butadiene as mediate elastic block chain. It helps to improve plasticity of S-EB-S and further improve bending resistance and fluidity of S-EB-S by using epoxy fatty acid ester and/or epoxy diluent with specific epoxy values as a crosslinker to control branched structure and molecular weight distribution.

In preferred embodiment, S-EB-S is preferably styrene-ethylene/butadiene-styrene triblock copolymer represented as a chemical structure according to Formula (1):

Wherein X is 150-240, Y and Z are 60-300. S-EB-S in the total composition grains is preferably 70 to 97 parts by weight based on 100 parts by weight of the composition grains. The case less than 70 parts by weight will lead to elasticity insufficient for masks. However, the case more than 97 parts by weight will lead to excessive hydrophobicity.

“Molecular weights” of the block copolymer refers to apparent molecular weight in kg/mol or number-average molecular weight (Mn) of the block copolymer, which can be measured with gel permeation chromatography (GPC) using a polystyrene calibration standard, such as is done according to ASTM D5296. “Number-average molecular weight” is also named as “styrene equivalent molecular weight” or “apparent molecular weight”. The molecular weight expressed herein are measured at the peak of the GPC trace, and commonly referred to as “styrene equivalent peak molecular weight”. The peak position is referenced because the difference between the peak molecular weight (Mp) and the number-average molecular weight is usually minor. When the contents of styrene and the vinyl group of the diene chain in the polymer are known, the styrene equivalent molecular weight can be converted into true molecular weight. In addition, butadiene equivalent molecular weight and butadiene equivalent peak molecular weight are also the same as aforesaid when GPC uses polybutadiene calibration standard for measurement. The apparent molecular weight differs from the absolute or true molecular weight when the composition of the polymer eluting through the GPC columns is different in composition from polystyrene. The peak molecular weight of the polystyrene block chain in S-EB-S is 16 Kg/mol to 25 Kg/mol, and the peak molecular weight of its polybutadiene block chain is 5 Kg/mol to 26 Kg/mol. The number-average molecular weight of S-EB-S is preferably 40 Kg/mol to 80 Kg/mol, more preferably 45 Kg/mol to 70 Kg/mol, and most preferably 50 Kg/mol to 60 Kg/mol. Otherwise, S-EB-S has adequate Melt Flow Index about 50 g/10 min to 100 g/10 min, preferably 65 g/10 min to 100 g/10 min, more preferably 75 g/10 min to 100 g/10 min at 230° C. of the temperature and 2.16 Kg of the pressure.

The method of the present invention fabricates the fiber of the non-woven fabric made of the composition grains that uniformly mixes the polyolefin based elastic copolymer and the hydrophilic auxiliary agent by using the meltblown process, which can embed the hydrophilic auxiliary agent in each fiber to allow water-absorbance of whole each fiber. Hence, the elastic hydrophilic non-woven fabric of the present invention can boost effects of absorbing beauty essence and care lotion. During the user applies a mask, each fiber gradually shrinks and lifts the skin as following evaporation after absorbing water and swelling, so that the mask made form the non-woven fabric of the present invention can lift the skin to achieve the effect of tightening the skin. To bring hydrophilicity into full play, the auxiliary agent is preferably 3 to 30 parts by weight in 100 parts by weight of the composition grains. The hydrophilic auxiliary agent, which is a polymer containing hydrophilic functional group, is preferably polylactic acid and polyvinyl acetate having biodegradability. Furthermore, polyvinyl acetate has elasticity and good hydrolysis ability. However, the case of addition more than 30 wt % of the hydrophilic auxiliary agent will lead the non-woven fabric to be too stiff and fragile and result in decrease of elongating ability. The hydrophilic auxiliary agent preferably at least comprises 50 wt %-80 wt % of polylactic acid and 20 wt %-50 wt % of polyvinyl acetate, so as to provided perfect constituent ratio of the prescription for the non-woven fabric acquiring balance between elasticity and hydrophilicity. The method can provide micron class diameter for the fiber of the non-woven fabric by melting the composition grains at high temperature to form the melt body to be adjusted Melt Flow Index in a range of 50 g/10 min to 100 g/10 min. In detail, a uniform fiber diameter about 2 μm to 20 μm can be obtained by the melt-blown process. In addition, the mask can also be made to have appropriate elasticity and softness by technical means of limiting the amount of each ingredient as described above. Appropriate elasticity allows the non-woven fabric of the present invention to provide a certain lifting force for the skin, and fully take advantage of tightening the skin. Appropriate softness allows the non-woven fabric of the present invention to comfortably fit the user's skin and bring better touch feeling for the skin.

The fabrication method for the elastic hydrophilic non-woven fabric is preferred to meltblown process. Please refer to FIGS. 1 and 2 . FIG. 1 is a schematic view depicting a flow chart of the fabrication method for the elastic hydrophilic non-woven fabric. FIG. 2 is a schematic view depicting the meltblown process on the composition grains. First, the fabrication method as depicted in FIG. 1 such that the following steps are include.

Step S1 is to prepare composition grains. Mix 3 to 30 parts by weight of the hydrophilic auxiliary agent and 70 to 97 parts by weight of S-EB-S as a raw material at room temperature to prepare composition grains. The hydrophilic auxiliary agent comprises polylactic acid with 50 wt % to 80 wt % and polyvinyl acetate with 20 wt % to 50 wt % based on a total weight of the hydrophilic auxiliary agent.

Step S2 is to form a melt body to be extruded and fed in. Wherein the melt body is form by melting composition grains at 200° C. to 250° C. As shown in FIG. 2 , the melt body 20 is firstly fed into and extruded out of an extruder (not shown), next the melt body 20 is fed into a die assembly 2 by means of a gear pump 1, then the melt body 20 is blown into the spinnerets 3 of the die assembly 2. Wherein a feeding temperature is perfectly in range of 150° C. to 160° C., a spinneret temperature is perfectly in range of 200° C. to 230° C., the extruding quantity of the extruder is perfectly in range of 100-50,000 mL/min.

Step S3 is to perform a meltblown process on the melt body that is squeezed by the spinneret to form fiber filaments. Keep heating at a first processing temperature from 200° C. to 230° C. after certain high velocity hot air 10 is continuously injected in the die assembly 2. The melt body 20 is forcedly blown out the spinnerets 3 and squeezed to form uniform fiber filaments by circulation therein and the hot air 10 is discharged out via surrounding of the spinnerets 3. Wherein a second processing temperature from 250° C. to 270° C. is taken as a meltblown and squeezed temperature. The parameters of the meltblown process are described as following: blowing speed, airflow pressure and temperature of the hot air 10 are 30 m/sec, 0.5 MPa, and in a range of 250° C. to 300° C. respectively.

Step S4 is to blow the meltblown fiber filaments to a conveyer, and lay these fiber filaments on the conveyer 4 to form a fibrous composite web 5 with thickness in range of 0.3-2.5 mm (as shown in FIG. 2 ) so that the fibrous composite web 5 is easy to divided in to fabrics with various shape.

In order to prove the features and practical effects for the embodiment category of the present invention, several exemplary examples and comparative examples are provided for performing following physical tests, and these test results are shown in table 1. First a synthesized example is provided for preparation of S-EB-S elastomer that is contained in test samples.

Test of Tensile Strength

According to CNS 14821 of tensile test method in the non-woven fabric for medical use, the tensile strength of each test sample was measured by using a textile tensile testing machine. Elasticity of the fabric is judged on basis of a draw ratio caused by a tension force. The draw ratio is represented as a percentage (%) which means to the length percent of encountering the tension force relative to an original state. The more the draw ratio surpasses 100%, the better the elasticity of the fabric is. On the contrary, the fabric is not obviously elastic when the draw ratio surpasses 100% in little. Said CNS14821 is a standard test method for physical properties of the non-woven fabric known to the skilled in the part, here is needless to tell more details. Operation parameters of the textile tensile testing machine are for example, 45 gsm of the non-woven fabric sample is taken with the size of 2.5 cm×15 cm, a clamping distance is 7.5 cm, a tension speed is 300 mm/min, a tension force in a machine direction (abbreviated as MD) is 0.5 Kgf, and the tension force in a cross direction (abbreviated as CD) is 0.388 Kgf.

Test of the Hygroscopic Metastatic Capability

It basically includes three aspects of the contact angle, time of water absorption and amount of liquid permeation. Here, a fiber surface of test samples is picked up for performing the tests in the contact angle, time of water absorption and amount of liquid permeation.

Test in the Contact Angle (θ)

Through the study of the contact angle, information about the solid-liquid intermolecular interaction can be obtained. Since the degree of the contact angle is inversely proportional to the degree of wetting (wettability), the relationship of wettability between the liquid and the solid surface can be determined. If the surface of the fabric is strong hydrophilicity (that is high wettability), as the tendency of the droplets to spread out and whole flat on the surface of the fabric increases, the contact angle decreases and is about 0 degree or closed to 180 degree, due to strong force which the droplets affected on the solid surface. On the contrary, if the surface of the fabric is strong hydrophobicity (that is low wettability), the contact angle is about 90 degree, due to very weak force which the droplets affected on the solid surface.

Test in Time of Water Absorption

In order to have better contacting feeling of refreshed dry comfort, nonwoven fabric is required to possess rapidity quality in water removal capability instead of keeping wet adhesive on the skin in wearing. Accordingly, by test the liquid moisture management properties of nonwoven fabric, the rapidity quality in water removal capability is indirectly obtained. Once the test samples got wetting in visual, the time until the surface of the test sample is wet is recorded as a wetting time, then the capability of moisture absorptivity can be indirectly obtained by evaluating the time of water absorption of fiber surface. The testing result for shorter wetting time means good rapidity quality in water removal capability, it is feasible to keep surficial dryness of the hydrophobic layer. On the contrary, the testing result for longer wetting time means bad rapidity quality in water removal capability, it is impossible to keep surficial dryness of the hydrophobic layer. In practical operation, each sample of exemplary examples and comparative examples was cut into 10 cm×10 cm. Then adequate amounts of water were added to soak each sample, and wetting on the surface of the fabric was observed, and the wetting time is recorded.

Test in Amount of Liquid Permeation

Each sample completely wetted by water was picked to be folded into a filter cup shape and disposed on a funnel. The funnel was placed in the beaker, and add enough water to the funnel. Once the sample allows the water to flow through, the water will flow downward and be collected in the beaker. Liquid permeability of the sample can be determined by measuring the amount of the water (mL) in the beaker. Liquid permeability is judged by the amount of water permeable to each sample in a certain period of time. The testing result for more water permeable means good performance in liquid permeability, and vice versa. Permeation time is the same 1 hour, and the amount of water permeable is measured by a graduated cylinder.

The embodiment provides a S-EB-S synthesized example to explain the following steps to fabricate S-EB-S elastomer contained in each sample.

Free radical polymerization step: 2000 g of cyclohexane, 1500 g of n-hexane and 1.75 g of tetrahydrofuran are added into a stainless-steel hydrogenation reaction kettle with magnetic rotary stirring, and uniformly mix them. 100 g of styrene is added for activation. Then 1.75 g of n-butyllithium initiator (20 wt % of effective component) is added as an initiator which accounts for 0.07% to 0.25% of the total mass of styrene and butadiene, and radical polymerization reaction is carried out at 40° C. to 55° C. and under the condition of 0.1 MPa to 0.5 MPa to generate a polystyrene chain segment;

Propagation step: 200 g of butadiene is added into the obtained polystyrene chain segment, butadiene accounts for 10% to 30% of the total mass of styrene and butadiene. And propagation reaction is carried out at 70° C. to 85° C. to generate a polystyrene-polybutadiene chain segment. Few amounts of potassium tert-butoxide is added as a regulator which accounts for 0.005% to 0.1% of the total mass of the solvent, and uniformly mix them. Simultaneously 125 g of styrene and 125 g of butadiene, which respectively accounts for 10% to 30% of the total mass of styrene and butadiene, are added. And propagation reaction is carried out at 70° C. to 95° C. and under the condition of 0.2 MPa to 0.5 MPa. Then 75 g of butadiene which accounts for 10% to 30% of the total mass of styrene and butadiene is added, and propagation reaction is carried out at 70° C. to 95° C. and under the condition of 0.2 MPa to 0.5 MPa;

Crosslinking step: few amounts of epoxy fatty acid methyl ester (molecular weight 312 and epoxy value 0.65) is added as a crosslinking agent with 0.1 to 0.5:1 of the molar ratios to the initiator. Tail end crosslinking reaction is carried out at 85° C. to 90° C. and under the condition of 0.2 MPa to 0.5 MPa to obtain a linear and branched polymer mixed glue solution;

Termination step: few amounts of ethanol with 1 to 1.2:1 of the molar ratio to the initiator is added into the mixed glue solution, and termination reaction is carried out at 70° C. to 80° C. to obtain a SBS glue solution; and

Hydrogenation step: 0.25 g of dibutyl titanate and 0.005 g of hexamethyl phosphoric triamine are added into the obtained SBS glue solution, and uniformly mix them. Then the hydrogen is introduced into the reaction kettle, keeping the pressure of the hydrogen in the reaction kettle at 1.5 MPa to 4 MPa, and hydrogenation reaction on the SBS glue solution is carried out at 70° C. to 90° C. to obtain a S-EB-S glue solution. After releasing pressure, an antioxidant (Irganox 1076 and W95 are mixed according to the weight ratio of 2:1) is added into the S-EB-S glue solution, and flash evaporation and concentration, devolatilization, and granulation are carried out a cutting to obtain a S-EB-S elastomer with 12 Kg/mol peak molecular weight of the polybutadiene block chain, 21 Kg/mol peak molecular weight of the polystyrene block chain, 54 Kg/mol number average molecular weight of the S-EB-S elastomer, 85 g/10 min of the Melt Flow Index under the condition of 230° C. and at 5 Kg of pressure, 30% of PSC, and 70° C. of glass transition temperature.

Exemplary Example 1

95 Kg of the S-EB-S elastomer and 5 Kg of the hydrophilic auxiliary agent are taken as the raw material to be blended and mixed to form the composition grains. Wherein the hydrophilic auxiliary agent comprises 20 wt % of polylactic acid and 80 wt % of polyvinyl acetate. The composition grains are melted at high temperature to form the melt body with 50 to 100 of Melt Flow Index (abbreviated as MI). Next, perform the meltblown process on the melt body to fabricate the non-woven fabric sample of exemplary example 1. During the meltblown process, the feeding temperature of the melt body 20 is set to 150° C., the temperature of the die assembly 2 is set to 210° C. After the melt body 20 entered the die assembly 2, the first processing temperature is set to 200° C., and the second processing temperature at which is meltblown and squeezed from the spinnerets 3 is set to 250° C. Airflow pressure, blowing speed and temperature of the hot air 10 are set to 0.5 MPa, 30 m/sec, and 250° C. respectively. Testing results in the non-woven fabric sample of exemplary example 1 include 300% of MD draw ratio, 210% of CD draw ratio, 120 degree of contact angle, 40 mins of wetting time, 60 mL/hr of liquid permeation. The non-woven fabric sample of exemplary example 1 has 2-10 μm of fiber diameter in micron class by observation in electron microscope.

Exemplary Example 2

90 Kg of the S-EB-S elastomer and 10 Kg of the hydrophilic auxiliary agent are taken as the raw material to be blended and mixed to form the composition grains. Wherein the hydrophilic auxiliary agent comprises 20 wt % of polylactic acid and 80 wt % of polyvinyl acetate. The composition grains are melted at high temperature to form the melt body with 50 to 100 of Melt Flow Index. Next, perform the meltblown process on the melt body to fabricate the non-woven fabric sample of exemplary example 2. During the meltblown process, the feeding temperature of the melt body 20 is set to 150° C., the temperature of the die assembly 2 is set to 210° C. After the melt body 20 entered the die assembly 2, the first processing temperature is set to 200° C., and the second processing temperature meltblown and squeezed from the spinnerets 3 is set to 250° C. Airflow pressure, blowing speed and temperature of the hot air 10 are set to 0.5 MPa, 30 m/sec, and 250° C. respectively. Testing results in the non-woven fabric sample of exemplary example 2 include 226% of MD draw ratio, 210% of CD draw ratio, 112 degree of contact angle, 20 mins of wetting time, 100 mL/hr of liquid permeation. The non-woven fabric sample of exemplary example 2 has 2-10 μm of fiber diameter in micron class by observation in electron microscope.

Comparative Example 1

95 Kg of the S-EB-S elastomer and 5 Kg of the hydrophilic auxiliary agent are taken as the raw material to be blended and mixed to form the composition grains. Wherein the hydrophilic auxiliary agent comprises 20 wt % of polylactic acid and 80 wt % of polyvinyl acetate. The composition grains are melted at high temperature to form the melt body with 50 to 100 of Melt Flow Index. Next, perform the meltblown process on the melt body to fabricate the non-woven fabric sample of comparative example 1. During the meltblown process, the feeding temperature of the melt body 20 is set to 200° C., the temperature of the die assembly 2 is set to 250° C. After the melt body 20 entered the die assembly 2, the first processing temperature is set to 240° C., and the second processing temperature meltblown and squeezed from the spinnerets 3 is set to 280° C. Airflow pressure, blowing speed and temperature of the hot air 10 are set to 0.5 MPa, 30 m/sec, and 250° C. respectively. Comparative example 1 has higher temperature in the meltblown process. Hence, the non-woven fabric is too stiff to fragile and has some clumps, so it is impossible for test of tensile strength. Testing results in the non-woven fabric sample of comparative example 1 include 128 degree of contact angle, 75 mins of wetting time, 10 mL/hr of liquid permeation. The non-woven fabric sample of comparative example 1 has 2-8 μm of fiber diameter in micron class by observation in electron microscope.

Comparative Example 2

50 Kg of the S-EB-S elastomer and 50 Kg of the hydrophilic auxiliary agent are taken as the raw material to be blended and mixed to form the composition grains. Wherein the hydrophilic auxiliary agent comprises 20 wt % of polylactic acid and 80 wt % of polyvinyl acetate. The composition grains are melted at high temperature to form the melt body with 50 to 100 of Melt Flow Index. Next, perform the meltblown process on the melt body to fabricate the non-woven fabric sample of comparative example 2. During the meltblown process, the feeding temperature of the melt body 20 is set to 150° C., the temperature of the die assembly 2 is set to 210° C. After the melt body 20 entered the die assembly 2, the first processing temperature is set to 200° C., and the second processing temperature meltblown and squeezed from the spinnerets 3 is set to 250° C. Airflow pressure, blowing speed and temperature of the hot air 10 are set to 0.5 MPa, 30 m/sec, and 250° C. respectively. Testing results in the non-woven fabric sample of comparative example 2 include 114% of MD draw ratio, 108% of CD draw ratio, 98 degree of contact angle, and wetting time is less than 1 minute after the non-woven fabric contacts with the water, then water directly flow through the non-woven fabric. The non-woven fabric sample of comparative example 2 has 2-10 μm of fiber diameter in micron class by observation in electron microscope.

TABLE 1 Samples Exemplary Exemplary Comparative Comparative example 1 example 2 example 1 example 2 Raw material 5 wt % 10 wt % 5 wt % 50 wt % 95 wt % auxiliary 90 wt % auxiliary 95 wt % auxiliary 50 wt % auxiliary S-EB-S agent S-EB-S agent S-EB-S agent S-EB-S agent MI 50-100 g/10 min Molecule weight 36500-75600 Processing Temp. feeding: 150° C. feeding: 150° C. feeding: 200° C. feeding: 150° C. first: 200° C. first: 200° C. first: 240° C. first: 200° C. second: 250° C. second: 250° C. second: 280° C. second: 250° C. Draw ratio MD: 300% MD: 226% Not available MD: 114% CD: 210% CD: 210% CD: 108% Contact angle 120 degree 112 degree 128 degree 98 degree Wetting time 40 mins 20 mins 75 mins <1 min Liquid permeation 60 mL/hr 100 mL/hr 10 mL/hr Flow through Fiber diameter 2-10 μm 2-10 μm 2-8 μm 2-10 μm

Exemplary example 1, Exemplary example 2, and Comparative example 2 are considered based on the same temperature conditions in the meltblown process but different composition conditions. The composition grains of Exemplary example 1 and Exemplary example 2 can be utilized to fabricate the elastic non-woven fabric with the draw ratio about 2 to 3 times because of containing more than 90 wt % of the S-EB-S elastomer. The non-woven fabrics of Exemplary example 1 and Exemplary example 2 are judged to be hydrophilic based on tests of contact angle, and excellent in hygroscopic metastatic capability as a result of relatively quick wetting time, perfect liquid permeability and more amounts of liquid permeation per hour. Otherwise, the composition grains of Comparative example 2 apparently got worse of the draw ratio due to containing less S-EB-S elastomer. Even if Comparative example 2 contained more hydrophilic auxiliary agents, its hydrophilicity is still worse than Exemplary example 1 and Exemplary example 2 based on tests of contact angle. Comparative example 2 is not good for hygroscopic metastatic capability as a result of relatively long wetting time and less amounts of liquid permeation per hour. With respect to temperature adjusting in the meltblown process, regardless of the same constituents in the composition grains of Comparative example 1 and Exemplary example 1, the non-woven fabric of Comparative example 1 is too stiff to fragile and its appearance looks clumped due to high feeding temperature, high first processing temperature and second processing temperature. In addition, the composition grains of Exemplary examples 1, 2 and Comparative examples 1, 2 can be utilized to fabricate the non-woven fabrics with uniform and fine fiber diameter because of adjusting MI to be in a range of 50 g/10 min to 100 g/10 min.

While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. 

What is claimed is:
 1. An elastic hydrophilic non-woven fabric, formed by a fiber made from composition grains using a meltblown process, the composition grains include 3 to 30 parts by weight of a hydrophilic auxiliary agent and 70 to 97 parts by weight of a hydrogenated styrene based triblock copolymer, the hydrophilic auxiliary agent includes a polylactic acid and a polyvinyl acetate.
 2. The elastic hydrophilic non-woven fabric according to claim 1, wherein the hydrophilic auxiliary agent at least includes the polylactic acid with 50 wt % to 80 wt % and the polyvinyl acetate with 20 wt % to 50 wt % based on a total weight of the hydrophilic auxiliary agent.
 3. The elastic hydrophilic non-woven fabric according to claim 1, wherein the hydrogenated styrene based triblock copolymer is selected-hydrogenated monoalkenyl arene-conjugated alkadiene-monoalkenyl arene.
 4. The elastic hydrophilic non-woven fabric according to claim 1, wherein the hydrogenated styrene based triblock copolymer has a chemical structure according to Formula (1),

 wherein X is an integer from 150 to 240, Y and Z are an integer from 60 to
 300. 5. The elastic hydrophilic non-woven fabric according to claim 1, wherein the fiber has a diameter from 2 μm to 20 μm.
 6. The elastic hydrophilic non-woven fabric according to claim 1, wherein after the composition grains are melted to be a melt body, the melt body has Melt Flow Index from 50 g/10 min to 100 g/10 min.
 7. The elastic hydrophilic non-woven fabric according to claim 1, wherein the elastic hydrophilic non-woven fabric is provided with 1.5 to 3 times of a draw ratio when encountering a tension force from 0.3 Kgf to 0.5 Kgf and 300 mm/min of a tension speed.
 8. A fabrication method for an elastic hydrophilic non-woven fabric, comprising following steps: forming grains, the grains are formed by mixing 3 to 30 parts by weight of a hydrophilic auxiliary agent and 70 to 97 parts by weight of a hydrogenated styrene based triblock copolymer, wherein the hydrophilic auxiliary agent includes polylactic acid and polyvinyl acetate; melting the grains to form a melt body; and performing a meltblown process on the melt body, the melt body is squeezed by a spinneret, and then formed a fiber for fabricating the elastic hydrophilic non-woven fabric.
 9. The fabrication method for an elastic hydrophilic non-woven fabric according to claim 8, wherein the meltblown process includes a processing temperature comprising a first processing temperature from 200° C. to 230° C. and a second processing temperature from 250° C. to 270° C.
 10. The fabrication method for an elastic hydrophilic non-woven fabric according to claim 8, wherein the meltblown process includes a feeding temperature from 150° C. to 160° C. 